BT Voyager 2100 wireless router/modem drops connection

anyone got any clues to the following...

just got a bt voyager 2100 modem router and setting it
up now..

I have installed an etec usb wired router modem and I am
hoping to change over to a wireless system as and when
I get the wireless cards.

So for now Im using the voyager using the network cable
supplied.

I had no probs with the etec modem - keeps connected top
speed all that.

But with the voyager I get connected but when I start newsbin
up and I start to use me full 1.5mb bandwidth I seem to lose
connection.

My Isp is Karoo and they are a little different to setup than most isps

will provide any extra info if anyone can help me..

thanks

Lee